Which description best explains how homeostasis is maintained in humans, including glucose regulation?

Which description best explains how homeostasis is maintained in humans, including glucose regulation?

• A. Negative feedback maintains set points via hormones (insulin/glucagon) and neural signals; integration ensures balance.
• B. Positive feedback maintains set points via hormones; neural signals are irrelevant.
• C. Homeostasis is only about body temperature, not glucose.
• D. Glucose regulation is controlled only by the liver, not hormones.

Answer: (A)

Maintaining stable blood glucose relies on negative feedback loops that use both hormones and neural signals to keep a set point. When blood glucose is high, the pancreas releases insulin, which tells liver, muscle, and fat tissues to take up glucose and store or convert it, bringing blood sugar down toward normal. When glucose is low, glucagon is released to signal the liver to break down glycogen and produce new glucose, raising blood sugar back to the set point. Neural inputs from the autonomic nervous system help coordinate these hormonal responses, ensuring a smooth, balanced return to the desired level. This integration of hormonal signals and neural control is what keeps the system from overshooting in either direction, which is the essence of negative feedback. In contrast, positive feedback would amplify changes rather than restore balance, so it’s not the mechanism used for glucose regulation. Also, while the liver plays a key role, it does not act alone; hormones coordinate across multiple tissues to maintain glucose homeostasis. Temperature regulation is another example of homeostasis, but glucose control illustrates how the body maintains more than one variable at once.

Maintaining stable blood glucose relies on negative feedback loops that use both hormones and neural signals to keep a set point. When blood glucose is high, the pancreas releases insulin, which tells liver, muscle, and fat tissues to take up glucose and store or convert it, bringing blood sugar down toward normal. When glucose is low, glucagon is released to signal the liver to break down glycogen and produce new glucose, raising blood sugar back to the set point. Neural inputs from the autonomic nervous system help coordinate these hormonal responses, ensuring a smooth, balanced return to the desired level. This integration of hormonal signals and neural control is what keeps the system from overshooting in either direction, which is the essence of negative feedback. In contrast, positive feedback would amplify changes rather than restore balance, so it’s not the mechanism used for glucose regulation. Also, while the liver plays a key role, it does not act alone; hormones coordinate across multiple tissues to maintain glucose homeostasis. Temperature regulation is another example of homeostasis, but glucose control illustrates how the body maintains more than one variable at once.